Bisphosphine process for producing the same and use thereof

ABSTRACT

Bisphosphines represented by the general formula (I) 
                         
wherein Ar 1  and Ar 2  each represents an arylene group which may be substituted; R 1  and R 2  each represents an alkyl group which may be substituted, or an aryl group which may be substituted, or R 1  and R 2  may combinedly form a ring together with the phosphorus atom bonded thereto; R 3 and R 4  each represents hydrogen atom or an alkyl group; and the carbon atoms each having R 3  and R 4  are bonded in positions ortho to the oxygen atom bonded to Ar 1  and Ar 2 ; process for production thereof; Group VIII metal complexes comprising said bisphosphines; and process for producing aldehydes, which comprises, on hydroformylation of ethylenically unsaturated compounds with carbon monoxide and hydrogen, using said Group VIII metal complexes.
 
     The hydroformylation of ethylenically unsaturated compounds according to the present invention can produce n-aldehydes at higher reaction rate and industrially more advantageously than with catalysts comprising conventional phosphines, while suppressing side re-actions such as hydrogenation and isomerization.

TECHNICAL FIELD

The present invention relates to novel bisphosphines, processes forproducing the same, and uses thereof.

The bisphospines provided by the present invention are useful ascomponents of the hydroformylation catalysts which are used onhydroformylation of ethylenically unsaturated compounds with carbonmonoxide and hydrogen to obtain the corresponding aldehydes.Accordingly, the above uses include Group VIII metal complexes that canact as hydroformylation catalysts and are obtainable by complexformation of the bisphosphines of the present invention and Group VIIImetal compounds, and also processes for producing aldehydes whichcomprises using the Group VIII metal complex catalysts ashydroformylation catalysts. On performing hydroformylation ofethylenically unsaturated compounds with carbon monoxide and hydrogen,use of such Group VIII metal complexes can produce the correspondingn-aldehydes at high reaction rate and with good selectivity, whilesuppressing side reactions such as hydrogenation and isomerization.

BACKGROUND ART

Reaction of ethylenically unsaturated compounds with hydrogen and carbonmonoxide in the presence of a Group VIII metal compound or metal complexcomprising such a Group VIII metal compound and a phosphorous compound,to produce the corresponding aldehydes is known as hydroformylation oroxo reaction. Production of aldedhydes by this reaction has been of highcommercial value.

For the hydroformylation, rhodium complexes comprising rhodium and aphosphorous compound are used as catalysts commercially. It is knownthat, with hydroformylation, the reaction rate and the selectivity to alinear aldehyde (hereinafter referred to as “n-aldehyde”) or a branchedaldehyde (hereinafter referred to as “iso-aldehyde”) dependsignificantly on the structure of the phosphorous compound constitutingthe catalyst used.

As the phosphorous compound, triphenylphospine, which is amonophosphine, is generally used commercially. In this case, theselectivity to n-aldehydes is low. In order to increase the selectivityto n-aldehydes, use of bisphosphines comprising two diphenylphosphinescrosslinked together via a specific divalent organic group (hereinafterthis group is referred to as “crosslinking group”) has been proposed.

For example, (1) it has been reported that with hydroformylation ofpropylene with use of 2,2′-bis(diphenylphosphinomethyl)biphenyl(hereinafter referred to as “BISBI”) the ratio of selectivities ton-aldehyde and iso-aldehyde (hereinafter referred to as “n/iso ratio”)is 25.1/1, which is markedly higher than 2.43/1, which is the case withtriphenylphosphine which is a monophosphine (see U.S. Pat. No.4,694,109); and (2) it is known that with hydroformylation of 1-octenewith use of 9,9-dimethyl-4,6-bis(diphenylphosphino)xanthene (hereinafterreferred to as “Xantphos”) the n/iso ratio is 53.5 [see Organometallics,14, 6, 3081–3089(1995)].

According to the knowledge of the present inventor, althoughhydroformylation of 7-octen-1-al with the above BISBI or Xantphos cansurely yield the corresponding n-aldehyde with higher selectivity thanthe reaction with triphenylphosphine, this reaction is not satisfactorydue to low catalytic activity and, further, has problems that sidereactions such as hydrogenation and isomerization occur.

With respect to the relationship between the structure of thebisphosphine used and the resulting n/iso ratio, it has been reportedthat, with a metal complex comprising a Group VIII metal compound and abisphosphine, the closer to 120° the angle formed byphosphorus-rhodium-phosphorus is, the higher the n/iso ratio is [seeJournal of the American Chemical Society, 114, 14, 5535–5543(1992) andOrganometallics, 14, 6, 3081–3089(1995)]. However, the above literaturereport nothing about the relationship between the structure of thebisphosphine used and the selectivity to side reactions such ashydrogenation and isomerization.

Accordingly, an object of the present invention is to provide abisphosphine constituting a hydroformylation catalyst that can, onhydroformylation of ethylenically unsaturated compounds, exert highcatalytic activity and yield n-aldehydes with high selectivity whilesuppressing side reactions such as hydrogenation and isomerization.

Another object of the present invention is to provide a process forproducing the above bisphosphine.

Still another object of the present invention is to provide a Group VIIImetal complex that can act as a hydroformylation catalyst, said complexcomprising the above bisphosphine and a Group VIII metal compound.

Yet another object of the present invention is to provide a process forproducing aldehydes which comprises effecting hydroformylation of anethylenically unsaturated compound with carbon monoxide and hydrogenwith use of the above Group VIII metal complex.

DISCLOSURE OF THE INVENTION

The present invention provides a bisphosphine having a crosslinkinggroup and represented by the general formula (I) (hereinafter referredto as “bisphosphine (I)”)

wherein Ar¹ and Ar² each represents an arylene group which may besubstituted; R¹ and R² each represents an alkyl group which may besubstituted or an aryl group which may be substituted, or R¹ and R² maycombinedly form a ring together with the phosphorus atom bonded thereto;R³ and R⁴ each represents hydrogen atom or an alkyl group; and thecarbon atoms each having R³ and R⁴ are bonded in positions ortho to theoxygen atom bonded to Ar¹ and Ar².

The present invention also provides a process for producing bisphosphine(I), which comprises subjecting a compound represented by the generalformula (II) (hereinafter referred to as “compound (II))X—CR³R⁴—A_(r) ¹—O—A_(r) ²—CR³R⁴—X  (II)wherein Ar¹, Ar², R³ and R⁴ are as defined above, and X represents anarylsulfonyloxy group, alkylsulfonyloxy group or a halogen atom;to phosphorylation with an alkali metal phosphide represented by thegeneral formula (III) (hereinafter referred to as “alkali metalphosphide (III)”)

wherein R¹ and R² are as defined above, M represents lithium atom,sodium atom or potassium atom.

The present invention further provides a Group VIII metal complexcomprising a Group VIII metal compound and a bisphosphine (I)(hereinafter referred to as “Group VIII metal complex (A)”).

The present invention still further provides a process for producingaldehydes, which comprises, on hydroformylation of an ethylenicallyunsaturated compound with carbon monoxide and hydrogen in the presenceof a catalyst to produce the corresponding aldehyde, using as thecatalyst the Group VIII metal complex (A).

MODES FOR CARRYING OUT THE INVENTION

Preferred examples of the arylene groups represented by Ar¹ and Ar² arethose having 6 to 20 carbon atoms. Concrete examples include phenylene,naphthylene and anthrathylene, 1,1′-biphenylene and 1,1′-binaphthylene.These arylene groups may be substituted. Examples of the substituentsare halogen atoms, e.g. fluorine atom, chlorine atom and bromine atom;alkyl groups having 1 to 6 carbon atoms, e.g. methyl, ethyl, propyl,isopropyl, butyl, isobutyl, s-butyl, t-butyl and cyclohexyl; fluoroalkylgroups having 1 to 3 carbon atoms, e.g. difluoromethyl, trifluoromethyl,1,1-difluoroethyl, 2,2-difluoroethyl and 1-fluoropropyl; alkoxy groupshaving 1 to 4 carbon atoms, e.g. methoxy, ethoxy, propoxy, isopropoxy,butoxy, isobutoxy, s-butoxy and t-butoxy; acyl groups having 2 to 4carbon atoms, e.g. acetyl, propionyl, butyryl and isobutyryl; acyloxygroups having 2 to 4 carbon atoms, e.g. acetyloxy, propionyloxy,butyryloxy and isobutyryloxy; alkoxycarbonyl groups having 2 to 5 carbonatoms, e.g. methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl,isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, s-butoxycarbonyland t-butoxycarbonyl; and carboxylic acid groups (hydroxycarbonylgroups) and salts thereof.

Preferred examples of the alkyl groups which may be represented by R¹ orR² are those having 1 to 6 carbon atoms. Concrete examples includemethyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl andcyclohexyl. These alkyl groups may be substituted. Examples of thesubstituents are halogen atoms, e.g. fluorine atom, chlorine atom andbromine atom; alkoxy groups having 1 to 4 carbon atoms, e.g. methoxy,ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, s-butoxy and t-butoxy;acyl groups having 2 to 4 carbon atoms, e.g. acetyl, propionyl, butyryland isobutyryl; acyloxy groups having 2 to 4 carbon atoms, e.g.acetyloxy, propionyloxy, butyryloxy and isobutyryloxy; alkoxycarbonylgroups having 2 to 5 carbon atoms, e.g. methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl,s-butoxycarbonyl and t-butoxycarbonyl; carboxylic acid groups and saltsthereof; and sulfonic acid groups and salts thereof.

Preferred examples of the aryl groups which may be represented by R¹ orR² are those having 6 to 14 carbon atoms. Concrete examples are phenyl,naphthyl and anthryl. These aryl groups may be substituted. Examples ofthe substituents are halogen atoms, e.g. fluorine atom, chlorine atomand bromine atom; alkyl groups having 1 to 6 carbon atoms, e.g. methyl,ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl andcyclohexyl; fluoroalkyl groups having 1 to 3 carbon atoms, e.g.difluoromethyl, trifluoromethyl, 1,1-difluoroethyl, 2,2-difluoroethyland 1-fluoropropyl; alkoxy groups having 1 to 4 carbon atoms, e.g.methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, s-butoxy andt-butoxy; acyl groups having 2 to 4 carbon atoms, e.g. acetyl,propionyl, butyryl and isobutyryl; acyloxy groups having 2 to 4 carbonatoms, e.g. acetyloxy, propionyloxy, butyryloxy and isobutyryloxy;alkoxycarbonyl groups having 2 to 5 carbon atoms, e.g. methoxycarbonyl,ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl,isobutoxycarbonyl, s-butoxycarbonyl and t-butoxycarbonyl; carboxylicacid groups and salts thereof; and sulfonic acid groups and saltsthereof.

R¹ and R² may combinedly form a ring together with the phosphorus atombonded thereto. Examples of such phosphorus-containing heterocyclic ringare 2,5-dimethylphospholane, 2,5-diethylphospholane,2,5-dipropylphospholane, 2,5-diisopropylphospholane,5H-Benzo[b]phosphindole, 5,10-dihydro-acryidophosphine,10H-Phenoxaphosphine, and 10-Phenothiaphosphine. Preferred examples ofthe alkyl groups which may be represented by R³ or R⁴ are those having 1to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl andisobutyl.

The bisphosphines (I) are novel compounds that have not been describedin the literature. The Group VIII metal complexes (A) comprising acomponent of bisphosphine (I) realize, as described later herein,excellent reaction results when used as hydroformylation catalysts.Preferred bisphosphines (I) are those with, in the general formula (I),Ar¹ and Ar² each representing phenylene, R¹ and R² each representingphenyl, and R³ and R⁴ each representing hydrogen. Representativeexamples of such bisphosphines (I) are2,2′-bis(diphenylphosphinomethyl)diphenyl ether,2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether and2,2′-bis(diphenylphosphinomethyl)-4-t-butyl diphenyl ether.

The process for producing bisphosphines (I) is now described.

The phosphorilation of a compound (II) with an alkali metal phosphide(III) is desirably carried out in the presence of a solvent. Examples ofpreferred solvents are ethers, e.g. 1,4-dioxane, dibutyl ether,2-ethoxyethyl ether, diethyleneglycol dimethyl ether, tetrahydrofuranand diethyl ether. Of these, a mixed solvent comprising tetrahydrofuranand dibutyl ether is suitable for use in the preparation of an alkalimetal phosphide (III) and further particularly desirable, since it canfacilitate ready separation of the resulting bisphosphine (I) from thealkali metal phosphide (III). The amount of the solvent used is notparticularly limited, but it is desirably in a range of 1 to 1000 partsby weight based on the weight of the alkali metal phosphide (III), morepreferably in a range of 10 to 100 parts by weight on the same basis,which insures high volume efficiency on separation of the bisphosphine(I) from the reaction mixture.

The above reaction is carried out by adding an alkali metal phosphide(III) dropwise into a solution containing a compound (II) or by addingdropwise a compound (II) into a solution containing an alkali metalphosphide (III).

The amount of the alkali metal phosphide (III) used is desirably in arange of 2 to 4 moles, more preferably in a range of 2 to 2.2 moles, permole of the compound (II), in view of easy separation of the resultingbisphosphine (I) from the unreacted alkali metal phosphide (III). Thereaction temperature is desirably in a range of −75° C. to the refluxtemperature of the solvent, more preferably in a range of −75° C. toroom temperature, since this range can suppress production ofbyproducts. The reaction time is desirably in a range of 0.5 to 10hours, more preferably in a range of 0.5 to 3 hours, which can suppressproduction of byproducts.

After completion of the reaction, to the reaction mixture containing thebisphosphine (I) as it is or, after the reaction mixture has beencondensed, to the condensate, a solvent suitable for water extractionsuch as toluene, pentane, hexane, diethyl ether, dipropyl ether, butylmethyl ether, tetrahydrofuran, methyl acetate, ethyl acetate or propylacetate is added. The solution is then washed with water, to separate anorganic layer. The bisphosphine (I) can be isolated and purified byrecrystallization or like processes from the organic layer.

The compounds (II) are roughly classified into sulfonic acid esters withX in the general formula (II) represents an arylsulfonyloxy oralkylsulfonyloxy group (hereinafter referred to as “sulfonic acid esters(II-a)”) and halides with X in the general formula (II) represents ahalogen atom (hereinafter referred to as “halides (II-b)”).

The sulfonic acid esters (II-a) can be produced by any known process.For example, 2,2′-bis(p-tolyl-sulfonyloxymethyl)-di(substituted)phenylether (hereinafter referred to as “sulfonic acid ester (II-a′)”), whichbelongs to the category of sulfonic acid esters (II-a), can be producedas follows.

In the above formulas, R^(a) and R^(b) each represents a substituent onthe benzene ring, such as a halogen atom, e.g. fluorine, chlorine andbromine; an alkyl group e.g. methyl, ethyl, propyl, isopropyl, butyl,isobutyl, s-butyl, t-butyl and cyclohexyl; a fluoroalkyl group, e.g.difluoromethyl, trifluoromethyl, 1,1-difluoroethyl, 2,2-difluoroethyland 1-fluoropropyl; an alkoxy group, e.g. methoxy, ethoxy, propoxy,isopropoxy, butoxy, isobutoxy, s-butoxy and t-butoxy; an acyl group,e.g. acetyl, propionyl, butyryl and isobutyryl; an acyloxy group, e.g.acetyloxy, propionyloxy, butyryloxy and isobutyryloxy; an alkoxycarbonylgroup, e.g. methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl,isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, s-butoxycarbonyland t-butoxycarbonyl; or a carboxylic acid group; Hal representschlorine atom or bromine atom; and Tos-Cl represents p-tolylsulfonylchloride.

(Description of Reaction II-a-1)

A hydroxyarene potassium salt (IV) is reacted with at least 1 molarequivalent of an arene halide (V) in the presence of activated copperpowder, to yield the corresponding diarene ether (VI). The reaction isdesirably carried out at the reflux temperature of the arene halide (V).After completion of the reaction, an organic solvent such as ether andwater are added to the reaction mixture and extraction is effected. Thediarene ether (VI) is isolated from the organic layer and purified, byvacuum distillation or like processes. [See Organic Syntheses, 2,446(1943).]

(Description of Reaction II-a-2)

The diarene ether (VI) is reacted with 2 molar equivalents of alithiaging agent in the presence of a solvent to yield the correspondingdilithiodiarene ether (VII). Examples of the lithiating agent are methyllithium, butyl lithium and phenyl lithium. Examples of the solvent arediethyl ether and tetrahydrofuran. The reaction temperature is selectedfrom a range below room temperature. [See The Journal of OrganicChemistry, 23, 10, 1476–1479(1958).]

(Description of Reaction II-a-3)

The reaction mixture prepared in Reaction II-a-2 and containingdilithiodiarene ether (VII) is reacted with at least 2 molar equivalentper mole of the dilithiodiarene ether (VII) of carbon dioxide, to yieldthe corresponding dicarboxydiarene ether (VIII). The reactiontemperature is selected from a range below room temperature. Aftercompletion of the reaction, the reaction mixture is condensed. To thecondensate an organic solvent such as ethyl acetate and water are addedand extraction is effected. The dicarboxydiarene ether (VIII) isisolated from the organic layer and purified, by recrystallization orlike processes. [See The Journal of Organic Chemistry, 55, 2,438–441(1990).]

(Description of Reaction II-a-4)

The dicarboxydiarene ether (VIII) in solid form is placed in a Soxlhet'sextractor. While solvent extraction is performed intermittently, thedicarboxydiarene ether (VIII) is reacted with at least 1 molarequivalent of lithium aluminumhydride, to yield the correspondingdihydroxyalkyldiarene ether (IX). An example of the solvent used isdiethyl ether. The reaction is desirably carried out at the refluxtemperature of the solvent used. After completion of the reaction, thereaction mixture is condensed. Water is added to the condensate andextraction is effected. The dihydroxyalkyldiarene ether (IX) is isolatedfrom the organic layer and purified, by recrystallization or likeprocesses. [See The Journal of Organic Chemistry, 34, 4,1165–1168(1969).]

(Description of Reaction II-a-5)

The dihydroxyalkyldiarene ether (IX) is reacted with 2 molar equivalentsof p-toluenesulfonyl chloride in the presence of an amine in an amountof at least 2 molar equivalents per mole of the former, to yield thecorresponding sulfonic acid ester (II-a′). An example of the amine ispyridine. The reaction temperature is selected from a range below roomtemperature. After completion of the reaction, the reaction mixture iscondensed. The sulfonic acid ester (II-a′) is isolated from thecondensate and purified, by recrystallization or like processes. [SeeThe Journal of the American Chemical Society, 74, 2, 425–428(1952).]

The halides (II-b) can be produced by any known process. For example,2,2′-bis(bromomethyl)-di-(substituted)phenyl ether (hereinafter referredto as “halide (II-b′)”) and 2,2′-bis(fluoromethyl)-di(substituted)phenylether (hereinafter referred to as “halide (II-b″)”), which belong to thecategory of halides (II-b), can be produced as follows.

In the above formulas, R^(c) and R^(d) each represents a substituent onthe benzene ring, such as a halogen atom, e.g. fluorine, chlorine andbromine; an alkyl group e.g. methyl, ethyl, propyl, isopropyl, butyl,isobutyl, s-butyl, t-butyl and cyclohexyl; a fluoroalkyl group, e.g.difluoromethyl, trifluoromethyl, 1,1-difluoroethyl, 2,2-difluoroethyland 1-fluoropropyl; an alkoxy group, e.g. methoxy, ethoxy, propoxy,isopropoxy, butoxy, isobutoxy, s-butoxy and t-butoxy; an acyl group,e.g. acetyl, propionyl, butyryl and isobutyryl; an acyloxy group, e.g.acetyloxy, propionyloxy, butyryloxy and isobutyryloxy; an alkoxycarbonylgroup, e.g. methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl,isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, s-butoxycarbonyland t-butoxycarbonyl; or a carboxylic acid group; NBS representsN-bromosuccinimide, Hal represents chlorine or bromine atom; and Tos-Clrepresents p-tolylsulfonyl chloride.

(Description of Reaction II-b-1)

A hydroxyarene potassium salt (X) is reacted with at least 1 molarequivalent of an arene halide (XI), to yield the corresponding diareneether (XII). The reaction is desirably carried out at the refluxtemperature of the arene halide (XI). After completion of the reaction,the reaction mixture is condensed. An organic solvent such as hexane andwater are added to the reaction mixture and extraction is effected. Thediarene ether (XII) is isolated from the organic layer and purified, byvacuum distillation or like means. [See The Journal of OrganicChemistry, 34, 4, 1165–1168(1969).]

(Description of Reaction II-b-2)

The diarene ether (XII) is reacted with at least 2 molar equivalents ofN-bromosuccinimide in the presence of a solvent to yield thecorresponding halide (II-b′). As the radical reaction initiator, forexample benzoyl peroxide is used. An example of the solvent is carbontetrachloride. The reaction is desirably carried out at the refluxtemperature of the solvent. After completion of the reaction, thereaction mixture is filtered and the filtrate is condensed. The halide(II-b′) is isolated from the condensate and purified, byrecrystallization or like processes. [See The Journal of OrganicChemistry, 34, 4, 1165–1168 (1969).]

(Description of Reaction II-b-3)

The dihydroxyalkyldiarene ether (XIII) is reacted with at least 2 molarequivalent of hydrogen bromide in the presence of a solvent, to yieldthe corresponding halide (II-b′). An example of the solvent is benzene.The reaction temperature is selected from a range below roomtemperature. After completion of the reaction, the reaction mixture iscondensed. The halide (II-b′) is isolated from the condensate andpurified, by recrystallization or like processes. [See The Journal ofOrganic Chemistry, 34, 4, 1165–1168(1969).]

(Description of Reaction II-b-4)

The sulfonic acid ester (XIV) is reacted with at least 2 molarequivalents of potassium fluoride in the presence of a solvent, to yieldthe corresponding halide (II-b″). An example of the solvent used isdiethylene glycol. The reaction temperature is selected from a rangebelow 130° C. After completion of the reaction, the halide (II-b″) isisolated from the reaction mixture and purified, by vacuum distillationor like processes. [See Chemistry Letters, 3, 265–268(1982).]

The alkali metal phosphides (III) can be produced by any known method.For example, alkali metal phosphides with M in the general formula (III)being lithium atom can be obtained by reacting the correspondingphosphines with a lithiaging agent. Alkali metal phosphide with M in thegeneral formula (III) being sodium or potassium atom can be obtained byreacting the corresponding phosphine halides with metallic sodium ormetallic potassium [See Chemische Berichte, 92, 1118–1126(1959)].

The Group VIII metal complexes (A) comprising a bisphosphine (I) and aGroup VIII metal compound are novel compounds that have not beendescribed in the literature. These complexes can act as catalysts forhydroformylation and exert high catalytic activity. These complexes can,when used for hydroformylation of ethylenically unsaturated compounds,produce n-aldehydes with high selectivity and suppress side reactionssuch as hydrogenation and isomerization.

The group VIII metal compound used for this purpose should eitheroriginally have the catalytic activity to accelerate hydroformylation ofethylenically unsaturated compounds or acquire such catalytic activityunder reaction conditions for the hydroformylation. Examples of suchmetal compound are those rhodium compounds, cobalt compounds, rutheniumcompounds and iron compounds that have been used as catalysts forhydroformylation. Examples of the rhodium compounds are rhodium oxides,e.g. RhO, RhO₂, Rh₂O and Rh₂O₃; rhodium salts, e.g. rhodium nitrate,rhodium sulfate, rhodium chloride, rhodium iodide and rhodium acetate;and rhodium complexes, e.g. Rh(acac)(CO)₂, RhCl(CO)(PPh₃)₂,RhCl(CO)(AsPh₃)₂, RhCl(PPh₃)₃, RhBr(CO)(PPh₃)₂, Rh₄(CO)₁₂, andRh₆(CO)₁₆. Examples of the cobalt compounds are cobalt complexes, e.g.HCo(CO)₃, HCo(CO)₄, Co₂(CO)₈ and HCo₃(CO)₉. Examples of the rutheniumcompounds are ruthenium complexes, e.g., Ru(CO)₃(PPh₃)₂, RuCl₂(PPh₃)₃,RhCl₃(PPh₃)₃ and Ru₃(CO)₁₂. Examples of the iron compounds are ironcomplexes, e.g. Fe(CO)₅, Fe(CO)₄PPh₃ and Fe(CO)₄(PPh₃)₂. Among thesecompounds, it is preferable to use rhodium compounds, for which mildconditions can be selected for hydroformylation, in particularRh(acac)(CO)₂.

The bisphophines (I) may be used singly or in combination of 2 or more,or further in combination with another phosphorous compound. Examples ofsuch other phosphorous compounds are phosphine, e.g. triethylphosphine,triisopropylphosphine, tributylphosphine, tricyclohexylphosphine,tribenzylphosphine, dimethylphenylphosphine, diethylphenylphosphine,methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine,cyclohexyldiphenylphosphine, 2-furyldiphenylphosphine,2-pyridyldiphenylphosphine, 4-pyridyldiphenylphosphine,triphenylphosphine, o-tolyldiphenylphosphine,diphenyl(pentafluorophenyl)phosphine, m-diphenylphosphinobenzenesulfonicacid and metal salts thereof, p-diphenylphosphinobenzoic acid and metalsalts thereof, p-diphenylphosphinophosphonic acid and metal saltsthereof, p-diphenylphosphinobenzenesulphonic acid and metal saltsthereof, bis(pentafluorophenyl)phenylphosphine,tris(p-fluorophenyl)phosphine, tris(pentafluorophenyl)phosphine,tris(p-chlorophenyl)phosphine, tri-o-tolylphosphine,tri-m-tolylphosphine, tri-p-tolylphosphine,tris(p-methoxyphenyl)phosphine andtris(p-N,N-dimethylaminophenyl)phosphine; and phosphites, e.g. triethylphosphite, triphenyl phosphite, tris(p-methylphenyl)phosphite,tris(p-trifluoromethylphenyl)phosphite, tris(p-methoxyphenyl)phosphite,tris(2,4-dimethylphenyl)phosphite andtris(2,4-di-t-butylphenyl)phosphite.

The bisphosphine (I) is used desirably in an amount of 2 to 10000 molesin terms of phosphorus atom per mole of the group VIII metal compoundused in terms of said group VIII metal atom, more preferably 2 to 1000moles in the same terms. If the amount of the bisphosphine (I) is lessthan this range, the catalyst will become unstable. Amounts exceedingthis range increase catalyst cost.

There are no specific restrictions with respect to the preparationprocess for the Group VIII metal complex (A). For example, the complexcan be prepared by a process which comprises separately preparing asolution of a Group VIII metal compound in a solvent that does notinfluence the hydroformylation and a solution of a bisphosphine (I)prepared in the same manner, introducing the two solutions separatelyinto a hydroformylation reactor and effecting reaction therein toproduce a complex. The complex can also be prepared by introducing abisphosphine (I) into the above Group VIII metal compound solution andthen adding a solvent that does not affect the hydroformylation, toobtain a homogeneous solution.

The process for hydroformylation of ethlenically unsaturated compoundswith carbon monoxide and hydrogen in the presence of a Group VIII metalcomplex (A), to produce the corresponding aldehydes is now described.

Ethylenically unsaturated compounds usable for this process can be anyof linear, branched and cyclic olefins, which have carbon-carbon doublebond in terminal or internal. Examples of such ethylenically unsaturatedcompounds are unsaturated aliphatic hydrocarbons, e.g. ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,2-butene, isobutene, 2-octene, 1,7-octadiene, vinylcyclohexene,cyclooctadiene, dicyclopentadiene, butadiene polymers and isoprenepolymers; styrenes, e.g. styrene, α-methylstyrene, β-methylstyrene,alkyl group-ring substituted styrenes and divinylbenzene; alicyclicolefin hydrocarbons, e.g. cyclopentene, cyclohexene,1-methylcyclohexene, cyclooctene and limonene; and functionalgroup-containing olefins, e.g. allyl alcohol, crotyl alcohol,3-methyl-3-buten-1-ol, 7-octen-1-ol, 2,7-octadienol, vinyl acetate,allyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate,allyl acrylate, vinyl methyl ether, allyl ethyl ether, 5-hexenamide,acrylonitrile and 7-octen-1-al.

The Group VIII metal complex (A) is used desirably in an amount of0.0001 to 1000 milligram-atom in terms of group VIII metal atom perliter of the reaction liquid, more preferably in an amount of 0.005 to10 milligram-atom in the same terms. Too small an amount of the GroupVIII metal complex (A) results in too low a reaction rate, while amountsexceeding this range increase the catalyst cost.

The hydroformylation is carried out either in the presence or absence ofa solvent. Examples of solvents usable for this purpose are aromatichydrocarbons, e.g. benzene, toluene, ethylbenzene, propylbenzene,butylbenzene, isobutylbenzene, s-butylbenzene, t-butylbenzene, o-xylene,m-xylene, p-xylene, o-ethyltoluene, m-ethyltoluene and p-ethyltoluene;saturated aliphatic hydrocarbons, pentane, hexane, heptane, octane,nonane, decane and cyclohexane; alcohols, e.g. methyl alcohol, ethylalcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutylalcohol, s-butyl alcohol, t-butyl alcohol, pentyl alcohol, isopentylalcohol, neopentyl alcohol, t-pentyl alcohol, 2-phenylethanol and2-phenoxyethanol; ethers, e.g. dimethyl ether, ethylmethyl ether,diethylether, dipropyl ether, butyl methyl ether, t-butyl methyl ether,dibutyl ether, ethyl phenyl ether, diphenyl ether, tetrahydrofuran,1,4-dioxane, ethylene glycol, propylene glycol, diethylene glycol,ethylene glycol monomethyl ether, ethylene glycol dimethyl ether,diethylene glycol diethyl ether, triethylene glycol, triethylene glycoldimethyl ether, tetraethylene glycol, tetraethylene glycol dimethylether, polyethylene glycol, polypropylene glycol, polyethylene glycolmonomethyl ether, polyethylene glycol dimethyl ether and polyethyleneglycol diethyl ether; esters, e.g. methyl acetate, ethyl acetate, propylacetate, butyl acetate, isopentyl acetate, phenyl acetate, methylpropionate, ethyl propionate, methyl benzoate and ethyl benzoate;ketones, e.g. acetone, ethyl methyl ketone, methyl propyl ketone, ethylketone, ethyl propyl ketone, dipropyl ketone, acetophenone, ethyl phenylketone, 1-phenyl-1-propanone, 1-phenyl-1-butanone and1-phenyl-2-propaneone; halohydrocarbons, e.g. chloromethane,dichloromethane, trichloromethane, tetrachloromethane, chloroethane,1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane,1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, 1,2-dichlorohexane,chlorobenzene, o-dichlorobenzene, m-dichlrobenzene, p-dichlrobenzene,1,2,3-trichlrobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene,fluoroethane, difluoromethane, 1,1-difluoroethane, fluorobenzene,o-fluorotoluene, m-fluorotoluene, p-fluorotoluene andα,α,α-trifluorotoluene; cyanohydrocarbons, e.g. acetonitrile,propionitrile, 1-cyanopropane, cyanobenzene, o-cyanotoluene,m-cyanotoluene and p-cyanotoluene; aprotic polar solvents, e.gN,N-dimethylformamide, hexamethylphosphoramide,1,3-dimethyl-2-imidazolidinone and 1-methyl-2-pyrrolidinone; and water.These solvents may be used singly or in combination of 2 or more. Thereis no particular limitation to the amount of the solvent used.

It is desirable that the mixed gas of hydrogen and carbon monoxide usedfor the hydroformylation have a H₂/CO molar ratio ranging from 0.1 to10, more preferably from 0.5 to 2, which ensures easy maintenance of themixed gas composition. The reaction pressure is desirably set to 0.1 to10 Mpa, more preferably 0.2 to 5 Mpa, in view of reaction rate. Thereaction temperature is desirably in a range of 40 to 150° C., morepreferably in a range of 60 to 130° C., which can suppress deactivationof the catalyst used. The reaction can be carried out in any ofstirred-type, liquid circulation-type, gas circulation-type, bubbledcolumn-type and like reactors. The reaction can be carried out eithercontinuously or batchwise.

Although there are no specific restrictions with respect to the methodof feeding starting materials, it is desirable to feed an ethylenicallyunsaturated compound, a Group VIII metal complex (A) solution preparedseparately and, as necessary, a solvent and then introduce a mixed gasof hydrogen and carbon monoxide under a prescribed pressure. Then thereaction is desirably effected with stirring at a prescribedtemperature.

The aldehydes obtained by the above process can be isolated and purifiedby any one of known processes. For example, the reaction mixture isdistilled to remove the solvent and unreacted ethylenically unsaturatedcompound, and the distillation residue is distilled to isolate and yieldthe product aldehyde with high purity. Or, prior to the distillation thecatalyst component may be separated by evaporation, extraction,adsorption or like known processes.

EXAMPLES

Hereinbelow, the present invention is described more concretely byreference to specific examples which are by no means limitative of theinvention. In the Examples that follow, unless otherwise specified,synthesis of phosphorus compounds was carried out under an atmosphere ofnitrogen or argon, and hydroformylations were all carried out under anatmosphere of a mixed gas having a H₂/CO ratio of 1.

Bisphosphines (I) and their precursors were identified with ¹H-NMRspectrograph (GSX-270, made by JEOL, LTd.) and/or ³¹P-NMR spectrograph(Lambda-500, made by JEOL, Ltd.). The values of chemical shifts of³¹P-NMR were based on the chemical shift of phosphoric acid set to 0ppm, where the latter had been previously determined on 20% by weightphosphoric acid in deuterated water.

Reference Example 1 Synthesis of 2,2′-dimethyldiphenyl ether

A 1-liter three-necked flask equipped with a reflux condenser, aDean-Stark apparatus, a dropping funnel, a thermometer and a mechanicalstirrer was charged with 40 g (0.71 mole) of potassium hydroxide, 77 g(0.71 mole) of o-cresol, 100 g (0.79 mole) of 2-chlorotoluene and 400 g(2.34 moles) of 2-bromotoluene. The three-necked flask was heated at150° C., while the water that generated was continuously removed fromthe flask using the Dean-Stark apparatus. Then 3 g of activated copperpowder was added and, while the water contained in the activated copperand 2-chlorotoluene were continuously removed from the reaction liquid,the flask was heated up to a liquid temperature of 190° C. Stirring wascontinued for 10 hours at the same temperature. After completion of thereaction, the reaction mixture was allowed to cool to room temperature.To the mixture 400 ml of diethyl ether was added, and the obtainedsolution was filtered through Celite. The filtrate was washed 5 timeseach with 200 ml of 5% by weight aqueous potassium hydroxide solution.The organic layer thus obtained was distilled in vacuo at 0.3 mmHg, togive 84 g of a distillate at 93° C. This distillate was colorless oilymatter and found to be 2,2′-dimethyldiphenyl ether having the followingproperties. The yield was 60% based on the o-cresol.

¹H-NMR (270 MHz, deuterated benzene, TMS, ppm) δ: 2.18 (s, 6H, Ar—CH ₃),6.67 (d, 2H), 6.80–7.00 (m, 4H), 7.05 (d, 2H).

Reference Example 2 Synthesis of 2,2′-bis(bromomethyl)diphenyl ether

A 500-ml three-necked flask equipped with a reflux condenser, athermometer and a mechanical stirrer was charged with 250 ml of carbontetrachloride, 58 g (0.33 mole) of N-bromosuccinimide and 32 g (0.16mole) of the 2,2′-dimethyldiphenyl ether synthesized in ReferenceExample 1. The contents were refluxed at a liquid temperature of 70° C.Then 1 g of benzoyl peroxide was added in 3 portions over 30 minutes andthe contents were further stirred for 30 minutes. The reaction mixturethus obtained was filtered and the filtrate was condensed and dried. Thedried matter was recrystallized from a solvent of hexane, to yield 20 gof a colorless crystal 2,2′-bis(bromomethyl)diphenyl ether having thefollowing properties. The yield was 35% based on the2,2′-dimethyldiphenyl ether.

¹H-NMR (270 MHz, deuterated benzene, TMS, ppm) δ: 4.30 (s, 4H, Ar—CH₂—Br), 6.58 (d, 2H), 6.73 (t, 2H), 6.83 (t, 2H), 7.04 (d, 2H).

Reference Example 3 Synthesis of 2-hydroxy-3-methoxytoluene

A 3-liter three-necked flask equipped with a thermometer and amechanical stirrer was charged with 300 g (1.97 moles) of o-vanillin,100 g of palladium-carbon supporting 5% by weight of palladium, 2 litersof ethyl acetate and 500 ml of acetic acid. The contents were stirredunder a hydrogen atmosphere and at room temperature, for 84 hours. Thereaction mixture thus obtained was filtered and the filtrate wascondensed. To the condensate, 2 liters of ethyl acetate was added again,and the mixture was washed with 1 liter of water three times. Theobtained organic layer was condensed and cooled, to yield 259 g ofcolorless crystal of 2-hydroxy-3-methoxytoluene having the followingproperties. The yield was 95% based on the o-vanillin.

¹H-NMR (270 MHz, deuterated benzene, TMS, ppm) δ: 2.28 ( s, 3H, Ar—CH₃), 3.19 (s, 3H, Ar—O—CH ₃), 5.78 (s, 1H, Ar—OH), 6.38 (d, 1H),6.63–6.80 (m, 2H).

Reference Example 4 Synthesis of 2,2′-dimethyl-6-methoxy-diphenyl ether

A 1-liter three-necked flask equipped with a reflux condenser, aDean-Stark apparatus, a dropping funnel, a thermometer and a mechanicalstirrer was charged with 500 ml of toluene, 36.5 g (0.65 mole) ofpotassium hydroxide and 90 g (0.65 mole) of the2-hydroxy-3-methoxytoluene synthesized in Reference Example 3. Thethree-necked flask was heated at 120° C., while the water that generatedwas continuously removed from the flask using the Dean-Stark apparatus.After the water removal, the solvent was removed mostly under reducedpressure. To the mixture, 10 g of activated copper powder and 700 g (4.1moles) of 2-bromotoluene were added and, while the water that generatedwas continuously removed from the reaction liquid using the Dean-Starkapparatus, the flask was heated up to a liquid temperature of 190° C.Stirring was continued for 10 hours at the same temperature. Aftercompletion of the reaction, the reaction mixture was allowed to cool toroom temperature. To the mixture 400 mL of diethyl ether was added, andthe obtained solution was filtered through Celite. The filtrate wasdistilled under a reduced pressure of 0.5 mmHg, to give a distillate at120° C. This distillate was recrystallized from a solvent of hexane, toyield 90 g of a colorless crystal of 2,2′-dimethyl-6-methoxy-diphenylether having the following properties. The yield was 61% based on the2-hydroxy-3-methoxytoluene.

¹H-NMR (270 MHz, deuterated benzene, TMS, ppm) δ:2.09 (s, 3H, Ar—CH ₃),2.49 (s, 3H, Ar—CH ₃), 3.18 (s, 3H, Ar—O—CH ₃), 6.50 (dd, 2H), 6.68–6.99(m, 4H), 7.09 (d, 1H).

Reference Example 5 Synthesis of2,2′-bis(bromomethyl)-6-methoxy-diphenyl ether

A 1-liter three-necked flask equipped with a reflux condenser, athermometer and a mechanical stirrer was charged with 450 ml of carbontetrachloride, 81 g (0.46 mole) of N-bromosuccinimide and 52 g (0.23mole) of the 2,2′-dimethyl-6-methoxy-diphenyl ether synthesized inReference Example 4. The contents were refluxed at a liquid temperatureof 70° C. Then 1 g of benzoyl peroxide was added in 3 portions over 30minutes and the contents were further stirred for 30 minutes. Thereaction mixture thus obtained was filtered and the filtrate wascondensed and dried. The dried matter was recrystallized from a solventof hexane, to yield 40 g of a colorless crystal of2,2′-bis(bromomethyl)-6-methoxy-diphenyl ether having the followingproperties. The yield was 45% based on the2,2′-dimethyl-6-methoxy-diphenyl ether.

¹H-NMR (270 MHz, deuterated benzene, TMS, ppm) δ: 3.04 (s, 3H, Ar—O—CH₃), 4.29 (s, 2H, Ar—CH₂—Br), 4.57 (s, 2H, Ar—CH ₂—Br), 6.34–6.45 (m,2H), 6.67 (t, 1H), 6.76–6.88 (m, 3H), 7.06 (d, 1H).

Example 1 Synthesis of 2,2′-bis(diphenylphosphinomethyl)-diphenyl ether

A 500-ml three-necked flask equipped with a reflux condenser, a droppingfunnel, a thermometer and a magnetic rotor was charged with 250 ml oftetrahydrofuran, and then 20 g (0.11 mole) of diphenylphosphine. Thecontents were cooled down to a liquid temperature of −75° C. Thereafter,69 ml (0.11 mole) of a 1.56 mole/l solution of butyl lithium in hexanewas added dropwise over 2 hours at such a rate as to maintain the liquidtemperature at −75 to −65° C. The contents were stirred for 1 hour atthe same temperature, to yield lithium diphenylphosphide. To thesolution, a solution of 19 g (0.054 mole) of the2,2′-bis(bromomethyl)diphenyl ether synthesized in Reference Example 2in 100 ml of tetrahydrofuran was added dropwise over 2 hours at such arate as to maintain the liquid temperature at −75 to −65° C. The mixturewas allowed to warm up to room temperature and stirred for 1 hour. Aftercompletion of the reaction, 250 ml of tetrahydrofuran was distilled offfrom the reaction mixture. To the residue, 200 ml of diethyl ether wasadded. The solution thus obtained was washed 3 times with 150 ml ofsaturated aqueous ammonium chloride solution and 3 times with 150 ml ofwater, to be subjected to extraction. The organic layer obtained wasdried over anhydrous magnesium sulfate and then filtered. The obtainedfiltrate was condensed to give an oily residue. To the condensate 200 mlof methanol was added and the mixture was boiled at the refluxtemperature of the solvent for 10 minutes, to yield 26 g of white powderof 2,2′-bis(diphenylphosphinomethyl)diphenyl ether having the followingproperties. The yield was 85% based on the 2,2′-bis(bromomethyl)diphenylether.

¹H-NMR (270 MHz, deuterated benzene, TMS, ppm) δ: 3.60 (s, 4H, Ar—CH₂—P), 6.67–6.78 (m, 4H), 6.85 (t, 2H), 6.95–7.10 (m, 14H, of which 12Hare P(C₆ H ₅)₂), 7.36–7.50 (m, 8H, P(C₆ H ₅)₂).

³¹P-NMR (500 MHz, deuterated benzene, phosphoric acid solution indeuterated water, ppm) δ: −11.2 (s).

Example 2

A 1-liter three-necked flask equipped with a reflux condenser, adropping funnel, a thermometer and a magnetic rotor was charged with 200ml of dibutyl ether, and then 10 g (0.44 mole) of metallic sodium. Thecontents were stirred at 100° C. for 0.5 hour, to give a dispersion ofmetallic sodium. To the dispersion, 48 g (0.22 mole) ofchlorodiphenylphosphine was added dropwise over 2 hours at such a rateas to maintain the liquid temperature at 100 to 110° C. After theaddition the mixture was stirred for 1 hour at the same temperature, togive sodium diphenylphosphide. The solution was then cooled to atemperature of 35° C., and 500 ml of tetrahydrofuran was added. To themixture, a solution of 39 g (0.11 mole) of the2,2′-bis(bromomethyl)diphenyl ether synthesized in Reference Example 2in 200 ml of tetrahydrofuran was added dropwise over 2 hours at such arate as to maintain the liquid temperature at −75 to −65° C. The mixturewas allowed to warm up to room temperature and stirred for 1 hour. Aftercompletion of the reaction, the solvent was mostly distilled off fromthe reaction mixture. To the residue, 400 ml of diethyl ether was added.The solution thus obtained was washed by extracting 3 times with 300 mlof saturated aqueous ammonium chloride solution and 3 times with 300 mlof water. The organic layer obtained was dried over anhydrous magnesiumsulfate and then filtered. The obtained filtrate was condensed to givean oily residue. To the condensate 400 ml of methanol was added and themixture was boiled at the reflux temperature of the solvent for 10minutes, to yield 42 g of white powder of2,2′-bis(diphenylphosphinomethyl)diphenyl ether having theabove-described properties. The yield was 68% based on the2,2′-bis(bromomethyl)diphenyl ether.

Example 3 Synthesis of2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether

A 500-ml three-necked flask equipped with a reflux condenser, a droppingfunnel, a thermometer and a magnetic rotor was charged with 200 ml oftetrahydrofuran, and then 9 g (0.049 mole) of diphenylphosphine. Thecontents were cooled to a liquid temperature of −75° C. To the mixture,31.5 ml (0.049 mole) of a 1.56 mole/l butyl lithium solution in hexanewas added dropwise over 2 hours at such a rate as to maintain the liquidtemperature at −75 to −65° C. After the addition the mixture was stirredfor 1 hour at the same temperature. To the mixture, a solution of 9.5 g(0.024 mole) of the 2,2′-bis(bromomethyl)-6-methoxy-diphenyl ethersynthesized in Reference Example 5 in 100 ml of tetrahydrofuran wasadded dropwise over 2 hours at such a rate as to maintain the liquidtemperature at −75 to −65° C. The mixture was allowed to warm up to roomtemperature and stirred for 1 hour. Then the mixture was allowed to warmup to room temperature and stirred for 1 hour. After completion of thereaction, 250 ml of the tetrahydrofuran was distilled off from thereaction mixture. To the residue, 200 ml of diethyl ether was added. Thesolution thus obtained was washed by extracting 3 times with 150 ml ofsaturated aqueous ammonium chloride solution and 3 times with 150 ml ofwater. The organic layer obtained was dried over anhydrous magnesiumsulfate and then filtered. The obtained filtrate was condensed to givean oily residue. To the condensate 20 ml of methanol was added and themixture was cooled to −50° C., to yield white solid, and this procedurewas repeated 3 times. The white powder thus obtained was dried underreduced pressure, to give 10 g of white powder of2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether having thefollowing properties. The yield was 70% based on the2,2′-bis(bromomethyl)-6-methoxy-diphenyl ether.

¹H-NMR (270 MHz, deuterated benzene, TMS, ppm) δ: 3.13 s, 3H, Ar—O—CH₃), 3.71 (s, 4H, Ar—CH ₂—P) , 6.42 (d, 1H), 6.53–6.66 (m, 2H), 6.77–6.92(m, 4H), 6.92–7.10 (m, 12H, P(C₆ H ₅)₂), 7.32–7.58 (m, 8H, P(C₆ H ₅)₂).³¹P-NMR (500 MHz, deuterated benzene, phosphoric acid solution indeuterated water, ppm) δ: −14.0 (s, 1P, MeO—Ar—CH₂—P), −11.4 ppm (s, 1P,Ar—CH₂—P).

Example 4 Hydroformylation of 7-octen-1-al using a catalyst of2,2′-bis(diphenylphosphinomethyl)diphenyl ether-Rhodium complex

A 100-ml three-necked flask equipped with a Teflon magnetic rotor wascharged with 3.9 mg (0.015 mmole) of Rh(acac)(CO)₂ and 84.9 mg (0.15mmole) of the 2,2′-bis(diphenylphosphinomethyl)diphenyl ethersynthesized in Example 1, and further with 6 ml of toluene. The mixturewas stirred at 50° C. for 30 minutes to become a homogeneous catalystsolution. A 50-ml three-necked flask equipped with a Teflon magneticrotor was charged with 3 ml of this catalyst solution and 27 ml (0.167mole; purity: 93%) of 7-octen-1-al. The mixture was then fed to a 100-mlautoclave equipped with a gas inlet and a sampling port. The insidepressure was raised with the mixed gas to 3.0 Mpa. With stirring theinside temperature was raised to 85° C. and reaction was effected for 6hours, to obtain 20.6 g (0.132 mole; yield: 79%) of 1,9-nonanedial and4.2 g (0.027 mole; yield: 16%) of 2-methyl-1,8-octanedial. Theconversion of 7-octen-1-al was 95% and the selectivities to n-aldehydeand iso-aldehyde were 83% and 18%, respectively. The n/iso ratio was4.88. No side reactions such as hydrogenation and isomerization wereobserved.

Example 5

Example 4 was repeated except that the inside pressure was changed from3.0 Mpa to 0.5 Mpa and that the reaction time was changed from 6 hoursto 4 hours, to obtain 22.2 g (0.142 mole; yield: 85%) of 1,9-nonanedialand 1.3 g (0.008 mole; yield: 5%) of 2-methyl-1,8-octanedial. Theconversion of 7-octen-1-al was 97% and the selectivities to n-aldehydeand iso-aldehyde were 88% and 5%, respectively. The n/iso ratio was17.6. The ratio of side reactions such as hydrogenation andisomerization was 7%.

Example 6

Example 4 was repeated except that 42.5 mg (0.075 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether was used, that theinside pressure was changed from 3.0 Mpa to 0.5 Mpa and that thereaction time was changed from 6 hours to 4 hours, to obtain 21.8 g(0.139 mole; yield: 84%) of 1,9-nonanedial and 1.5 g (0.010 mole; yield:6%) of 2-methyl-1,8-octanedial. The conversion of 7-octen-1-al was 96%and the selectivities to n-aldehyde and iso-aldehyde were 87% and 6%,respectively. The n/iso ratio was 14.5. The ratio of side reactions suchas hydrogenation and isomerization was 7%.

Example 7 Hydroformylation of 7-octen-1-al using a catalyst of2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether-Rhodiumcomplex

Example 4 was repeated except that 89.5 mg of the2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether synthesizedin Example 3 was used instead of 84.9 mg (0.15 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether was used, and that thereaction time was changed from 6 hours to 8 hours, to obtain 21.1 g(0.135 mole; yield: 81%) of 1,9-nonanedial and 4.0 g (0.026 mole; yield:15%) of 2-methyl-1,8-octanedial. The conversion of 7-octen-1-al was 96%and the selectivities to n-aldehyde and iso-aldehyde were 84% and 16%,respectively. The n/iso ratio was 5.25. No side reactions such ashydrogenation and isomerization were observed.

Example 8 Hydroformylation of 1-octene using a catalyst of2,2′-bis(diphenylphosphinomethyl)diphenyl ether-Rhodium complex

A 100-ml three-necked flask equipped with a Teflon magnetic rotor wascharged with 3.9 mg (0.015 mmole) of Rh(acac)(CO)₂ and 42.5 mg (0.075mmole) of the 2,2′-bis(diphenylphosphinomethyl)diphenyl ethersynthesized in Example 1, and further with 6 ml of toluene. The mixturewas stirred at 50° C. for 30 minutes to become a homogeneous catalystsolution. A 50-ml three-necked flask equipped with a Teflon magneticrotor was charged with 3 ml of this catalyst solution and 27 ml (0.172mole; purity: at least 99%) of 1-octene. The mixture was then fed to a100-ml autoclave equipped with a gas inlet and a sampling port. Theinside pressure was raised with the mixed gas to 1.0 Mpa. With stirringthe inside temperature was raised to 85° C. and reaction was effectedfor 5 hours, to obtain 21.2 g (0.149 mole; yield: 87%) of nonanal and1.5 g (0.011 mole; yield: 6%) of 2-methyloctanal. The conversion of1-octene was 98% and the selectivities to n-aldehyde and iso-aldehydewere 89% and 6%, respectively. The n/iso ratio was 14.8. The ratio ofside reactions such as hydrogenation and isomerization was 5%.

Example 9 Hydroformylation of 1-octene using a catalyst of2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether-Rhodiumcomplex

Example 8 was repeated except that 44.8 mg (0.075 mmole) of the2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether synthesizedin Example 3 was used instead of 42.5 mg (0.075 mmole) of the2,2′-bis(diphenylphosphinomethyl)diphenyl ether, to obtain 21.3 g (0.150mole; yield: 87%) of nonanal and 1.5 g (0.010 mole; yield: 6%) of2-methyloctanal. The conversion of 1-octene was 98% and theselectivities to n-aldehyde and iso-aldehyde were 89% and 6%,respectively. The n/iso ratio was 14.8%. The ratio of side reactionssuch as hydrogenation and isomerization was 5%.

Comparative Example 1 Hydroformylation of 7-octen-1-al using a catalystof triphenylphosphine-Rhodium complex

Example 4 was repeated except that 78.7 mg (0.3 mmole) oftriphenylphosphine was used instead of 84.9 mg (0.15 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether, and that the reactiontime was changed from 6 hours to 8 hours, to obtain 17.8 g (0.114 mole;yield: 68%) of 1,9-nonanedial and 7.0 g (0.045 mole; yield: 27%) of2-methyl-1,8-octanedial. The conversion of 7-octen-1-al was 95% and theselectivities to n-aldehyde and iso-aldehyde were 72% and 28%,respectively. The n/iso ratio was 2.57. No side reactions such ashydrogenation and isomerization were observed.

Comparative Example 2

Hydroformylation of 7-octen-1-al using a catalyst of BISBI-Rhodiumcomplex

Example 4 was repeated except that 82.6 mg (0.15 mmole) of BISBI wasused instead of 84.9 mg (0.15 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether, and that the reactiontime was changed from 6 hours to 10 hours, to obtain 23.1 g (0.148 mole;yield: 88%) of 1,9-nonanedial and 0.7 g (0.005 mole; yield: 3%) of2-methyl-1,8-octanedial. The conversion of 7-octen-1-al was 95% and theselectivities to n-aldehyde and iso-aldehyde were 93% and 3%,respectively. The n/iso ratio was 31.00. The selectivity to sidereactions such as hydrogenation and isomerization was 4%.

Comparative Example 3 Hydroformylation of 7-octen-1-al using a catalystof Xantphos-Rhodium complex

Example 4 was repeated except that 86.7 mg (0.15 mmole) of Xantphos wasused instead of 84.9 mg (0.15 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether, and that the reactiontime was changed from 6 hours to 15 hours, to obtain 22.1 g (0.141 mole;yield: 85%) of 1,9-nonanedial and 0.9 g (0.006 mole; yield: 4%) of2-methyl-1,8-octanedial. The conversion of 7-octen-1-al was 89% and theselectivities to n-aldehyde and iso-aldehyde were 95% and 4%,respectively. The n/iso ratio was 23.75. The selectivity to sidereactions such as hydrogenation and isomerization was 1%.

Comparative Example 4 Hydroformylation of 1-octene using a catalyst oftriphenylphosphine-Rhodium complex

Example 8 was repeated except that 39.4 mg (0.15 mmole) oftriphenylphosphine was used instead of 42.5 mg (0.075 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether and that the reactiontime was changed from 5 hours to 8 hours, to obtain 16.4 g (0.115 mole;yield: 67%) of nonanal and 5.5 g (0.039 mole; yield: 22%) of2-methyloctanal. The conversion of 1-octene was 98% and theselectivities to n-aldehyde and iso-aldehyde were 68% and 23%,respectively. The n/iso ratio was 2.96. The ratio of side reactions suchas hydrogenation and isomerization was 9%.

Comparative Example 5 Hydroformylation of 1-octene using a catalyst ofBISBI-Rhodium complex

Example 8 was repeated except that 41.3 mg (0.075 mmole) of BISBI wasused instead of 42.5 mg (0.075 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether and that the reactiontime was changed from 5 hours to 10 hours, to obtain 21.4 g (0.151 mole;yield: 88%) of nonanal and 0.29 g (0.002 mole; yield: 1%) of2-methyloctanal. The conversion of 1-octene was 98% and theselectivities to n-aldehyde and iso-aldehyde were 89% and 1%,respectively. The n/iso ratio was 89.0. The ratio of side reactions suchas hydrogenation and isomerization was 10%.

Comparative Example 6 Hydroformylation of 1-octene using a catalyst ofXantphos-Rhodium complex

Example 8 was repeated except that 43.4 mg (0.075 mmole) of Xantphos wasused instead of 42.5 mg (0.075 mmole) of2,2′-bis(diphenylphosphinomethyl)diphenyl ether and that the reactiontime was changed from 5 hours to 15 hours, to obtain 19.4 g (0.136 mole;yield: 79%) of nonanal and 0.39 g (0.003 mole; yield: 2%) of2-methyloctanal. The conversion of 1-octene was 86% and theselectivities to n-aldehyde and iso-aldehyde were 92% and 2%,respectively. The n/iso ratio was 46.0. The ratio of side reactions suchas hydrogenation and isomerization was 6%.

In the hydroformylation of 7-octen-1-al, comparison of Examples 4 and 7with Comparative Examples 2 and 3 reveals that Group VIII metalcomplexes (A) comprising bisphosphines can exert higher catalyticactivity than Group VIII metal complexes comprising known bisphosphinesand, further, cause no side reactions such as hydrogenation andisomerization. Besides, as shown in Examples 5 and 6, changing thereaction conditions employed in Example 4 can increase the n/iso ratioand catalytic activity. On the other hand, comparison of Examples 4 and7 with Comparative Example 1 reveals that Group VIII metal complexes (A)comprising bisphosphines (I), cause, similarly to a commerciallyemployed Group VIII metal complex comprising triphenylphosphine, no sidereactions such as hydrogenation and isomerization, while the former hashigher n/iso ratio and catalytic activity than the latter.

In the hydroformylation of 1-octene, comparison of Examples 8 and 9 withComparative Examples 5 and 6 reveals that Group VIII metal complexes (A)comprising bisphosphines (I) can exert higher catalytic activity thanGroup VIII metal complexes comprising known bisphosphines and, further,suppress side reactions such as hydrogenation and isomerization. On theother hand, comparison of Examples 8 and 9 with Comparative Example 4reveals that Group VIII metal complexes (A) comprising bisphosphines (I)can suppress side reactions such as hydrogenation and isomerization to alower level and achieve higher n/iso ratio and catalytic activity than aGroup VIII metal complex comprising a commercially employedtriphenylphosphine.

INDUSTRIAL APPLICABILITY

According to the present invention, there are provided hydroformylationcatalysts comprising Group VIII metal complex (A) that can, onhydroformylation of ethylenically unsaturated compounds, exert highcatalytic activity and yield n-aldehydes with high selectivity whilesuppressing side reactions such as hydrogenation and isomerization, andbisphosphines (I) constituting such complexes and process for productionthereof.

According to the present invention, use of the Group VIII metalcomplexes (A) for hydroformylation of ethylenically unsaturatedcompounds with carbon monoxide and hydrogen can lead to production ofthe corresponding n-aldehydes at high reaction rate and with highselectivity, while suppressing side reactions such as hydrogenation andisomerization.

1. A bisphosphine which is 2,2′-bis(diphenylphosphinomethyl)diphenylether, 2,2′-bis(diphenylphosphinomethyl)-6-methoxy-diphenyl ether, or2,2′-bis(diphenylphosphinomethyl)-4-t-butyl-diphenyl ether.
 2. A processfor producing a bisphosphine of claim 1,

which comprises: subjecting a compound represented by formula (II)

 wherein Ar¹ and Ar² each represents a phenylene group and each togetherare optionally substituted by 6-methoxy or optionally by 4-t-butyl, R³and R⁴ each represents a hydrogen atam, and X represents anarylsulfonyloxy group, alkylsulfonyloxy group or a halogen atom tophosphorylation with an alkali metal phosphide represented by formula(III)

 wherein R¹ and R² are each phenyl and M represents lithium atom, asodium atom or potassium atom.
 3. The process according to claim 2,wherein said phosphorization is carried out in the presence of anether-based solvent.
 4. The process according to claim 3, wherein saidether-based solvent is selected from the group consisting of1,4-dioxane, dibutyl ether, 2-ethoxyethyl ether, diethyleneglycoldimethyl ether, tetrahydrofuran and diethyl ether.
 5. The processaccording to claim 3, wherein said solvent comprises a mixed solventcomprising tetrahydrofuran and dibutyl ether.
 6. The process accordingto claim 2, wherein said alkali metal phosphide is used in an amountranging from 2 to 4 moles per mole of said compound represented by thegeneral formula (II).
 7. The process according to claim 6, wherein saidalkali metal phosphide is used in an amount ranging from 2 to 2.2 molesper mole of said compound represented by the general formula (II).
 8. AGroup VIII metal complex, comprising: a bisphosphine of claim 1

 and a Group VIII metal compound.
 9. The Group VIII metal complexaccording to claim 8, wherein said Group VIII metal compound is arhodium compound, cobalt compound, ruthenium compound or iron compoundhaving catalytic activity for hydroformylation.
 10. The Group VIII metalcomplex according to claim 9, wherein said Group VIII metal compound isa rhodium compound selected from the group consisting of RhO, RhO₂,Rh₂O, Rh₂O₃, rhodium nitrate, rhodium sulfate, rhodium chloride, rhodiumiodide, rhodium acetate, Rh(acac)(CO)₂, RhCl(CO)(PPh₃)₂,RhCl(CO)(AsPh₃)₂, RhCl(PPh₃)₃, RhBr(CO)(PPh₃)₂, RH₄(CO)₁₂ and Rh₆(CO)₁₆.11. The Group VIII metal complex according to claim 10, wherein saidGroup VIII metal compound is Rh(acac)(CO)₂.
 12. The Group VIII metalcomplex according to claim 8, wherein the amount of said bisphosphineused is in a range of 2 to 10000 moles in terms of phosphorus atom permole of said Group VIII metal compound in terms of Group VIII metalatom.
 13. The Group VIII metal complex according to claim 12, whereinthe amount of said bisphosphine used is in a range of 2 to 1000 moles interms of phosphorus atom per mole of said Group VIII metal compound interms of Group VIII metal atom.
 14. A process for producing aldehydes,which comprises: hydroformylating ethylenically unsaturated compoundswith carbon monoxide and hydrogen in the presence of a catalyst of aGroup VIII metal complex as defined in claim 8 to produce thecorresponding aldehydes.
 15. The process according to claim 14, whereina mixed gas comprising carbon monoxide and hydrogen having a H₂/CO molarratio of 0.1 to 10 is fed into the reaction.
 16. The process accordingto claim 15, wherein a said mixed gas comprising carbon monoxide andhydrogen has a H₂/CO molar ratio of 0.5 to
 2. 17. The process accordingto claim 14, wherein the reaction pressure is in a range of 0.1 to 10Mpa.
 18. The process according to claim 17, wherein the reactionpressure is in a range of 0.2 to 5 Mpa.
 19. The process according toclaim 14, wherein the reaction temperature is in a range of 40 to 150°C.
 20. The process according to claim 19, wherein the reactiontemperature is in a range of 60 to 130° C.
 21. The process according toclaim 14, wherein the amount of said Group VIII metal complex is in arange of 0.0001 to 1000 milligram-atom in terms of the Group VIII metalatom per liter of the reaction liquid.
 22. The process according toclaim 21, wherein the amount of said Group VIII metal complex is in arange of 0.005 to 10 milligram-atom in terms of the Group VIII metalatom per liter of the reaction liquid.